Domino Dearomative Iodocyclization/Intramolecular Diels–Alder Reaction for Rapid Construction of Polycyclic Scaffolds

We report a domino dearomative iodocyclization/intramolecular Diels–Alder (IMDA) reaction sequence that converts planar aromatic precursors into complex three-dimensional polycyclic scaffolds. The initial dearomative iodocyclization affords spirodienones, which can serve as dienophiles for a subsequent IMDA reaction with an internal diene. This protocol simultaneously creates three C–C bonds, three rings, and five stereocenters in a single step with excellent diastereoselectivity. This protocol is applicable to a broad range of substituents and ring systems for achieving iodinated, sp 3 -rich polycycles.